Subscribe free to our newsletters via your
  Solar Energy News  




Subscribe free to our newsletters via your




















SOLAR DAILY
An ordered route to improved performance of solar cells
by Staff Writers
Thuwal, Saudi Arabia (SPX) Jan 11, 2017


File image.

Silicon is the dominant material in the production of solar cells. However, perovskites are catching up: they are cheap, flexible and have a promising light-to-electricity conversion efficiency. KAUST researchers are investigating the formation of these perovskites to better understand their properties and gain insight into the design of more efficient devices1.

Metal halide perovskites have three components: a metal (often lead), a halogen (commonly iodine although chlorine or bromine are also candidates) and an organic (usually methylammonium). Thin films of these materials can be created by combining methylammonium iodine (MAI) and a lead salt that provides the additional halogen atoms required, such as PbI2, PbBr2 or PbCl2, in a solvent. A drop on a substrate is quickly rotated to create a film and then heated to form the desired solid polycrystalline perovskite material.

The beauty of this approach is its simplicity; however, what happens during the process is not entirely clear. As a result, reproducibility across laboratories has been unsuccessful, with different groups creating samples with different properties.

Aram Amassian, KAUST Associate Professor of Material Science and Engineering, and fellow researchers from the University's Solar Center used bright X-rays at the Cornell High Energy Synchrotron Source in New York, U.S. to observe this one-step solution-coating process in real time. This technology allowed them to identify that the conversion of the perovskite solution to the perovskite crystalline solid occurs via an intermediate solid state that is highly solvated.

"We show that the nature and the stability of this solvated precursor state is crucial to the reproducibility of the final product," said Amassian.

The team measured the changes in film thickness during spinning with the common solvent N,N-dimethylformamide. Using an optical reflective measurement, the team identified that the thickness of the film evolved over time depending on the ratio of MAI to lead salt and that when the concentration of MAI was increased, the solution thinned much slower, strongly impacting the film's formation behavior.

This effect is not evident in other material systems used in other similar technologies, such as organic solar cells, providing the first clue that solvent-solute interactions are very important in halide perovskites.

"We then used synchrotron X-ray scattering during spinning to find out more about this intermediate precursor," explained Amassian. "We identified that the precursor existed in either a crystalline or a disordered state within 15 to 20 s of spinning."

Regardless of time delay, the precursors in the crystalline state were stable in time and converted reliably into perovskite films with consistent microstructure and morphology such that their surface coverage and shape were reproducible. Meanwhile, precursors in the disordered state were sensitive to time, causing large variability in the properties of the resultant material and the performance of the solar cells.

Research paper


Comment on this article using your Disqus, Facebook, Google or Twitter login.

.


Related Links
King Abdullah University of Science and Technology
All About Solar Energy at SolarDaily.com






Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

Previous Report
SOLAR DAILY
Epiphany School installs 25 kW solar PV system through partnership with Solect Energy
Dorchester MA (SPX) Jan 10, 2017
Epiphany School, an independent, tuition-free middle school dedicated to serving children from economically disadvantaged families, has partnered with Solect Energy of Hopkinton, MA to install a 25 kilowatt (kW) solar energy system on the roof of its Dorchester location. The solar array is expected to cover a portion of the school's annual electricity use. Founded in 1997, Epiphany School ... read more


SOLAR DAILY
Dual-purpose biofuel crops could extend production, increase profits

Open-source plant database confirms top US bioenergy crop

WSU researchers discover unique microbial photosynthesis

Potential biofuel crops in Hawaii may successfully sequester carbon in soil

SOLAR DAILY
Baidu family robot a Chinese spin on Amazon Echo

Amazon Alexa virtual assistant shines at tech show

Bionic woman: Chinese robot turns on the charm

For 'intelligent' robot, chess is just a hobby

SOLAR DAILY
New York sets bar high for offshore wind

The answer is blowing in the wind

French power group aims to double wind capacity

New rules for micro-grids in Alberta

SOLAR DAILY
New technology will cut plug-in hybrid fuel consumption by one third

VW directors knew of emissions scandal earlier: press

NAVYA Self-driving shuttle goes to work in Las Vegas

Cadillac keeps plan to sell Chinese-made cars in US

SOLAR DAILY
Scientists discover a molecular motor has a 'gear' for directional switching

Rolling out an e-sticker revolution

Tenfold jump in green tech needed to meet global emissions targets

Tesla starts mass production of batteries

SOLAR DAILY
France sells off Engie stake to finance Areva rescue

EU clears French rescue of troubled nuclear firm Areva

UK asks regulators to assess Chinese nuclear reactor

Controversial nuclear power plant near New York to close

SOLAR DAILY
China to build $1.5 billion power line across Pakistan

MIT Energy Initiative report provides guidance for evolving electric power sector

Toward energy solutions for northern regions

Energy-hungry Asia slowing down, lender says

SOLAR DAILY
In cool forests, foraging bees prefer the warmth of darker flower petals

Scientists try turning Christmas trees into plastic

Obama creates two new national monuments

Amazonia's best and worst areas for carbon recovery revealed




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News








The content herein, unless otherwise known to be public domain, are Copyright 1995-2017 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement